1. Field of the Invention
This invention relates to electrically driven single occupant transporters such as wheelchairs and scooters used by handicapped persons, and more particularly concerns apparatus for achieving safe stopping of such transporters.
2. Description of the Prior Art
Electrically driven transporters such as wheelchairs and scooters are in widespread use for providing independent mobility to a single seated handicapped person. Control of the movement of such transporters by the occupant is generally achieved by way of manual manipulation of a joystick lever positioned within or adjacent an arm rest of the transporter, particularly in wheelchairs. Appropriate movement of the joystick produces forward, rearward, or turning motions, and controls the speed of the wheelchair in the chosen direction. Stopping or braking of the wheelchair is generally produced by pressing a button or moving the joystick to a centered “OFF” position.
U.S. Pat. Nos. 4,415,049; 4,489,256; 4,805,711; 4,978,899 and 6,072,292 relate to the securement of reasonably smooth braking of wheelchairs based upon manipulation of the joystick in conjunction with electrical features of motors that drive the wheels. However, all of said braking systems assume that the occupant is in complete and competent control of the operation of the wheelchair, and do not contemplate emergency stopping situations or inadequate attentiveness to prevent accidents.
Most persons using electrically driven wheelchairs are elderly or feeble, or may have diminished alertness. When they get out of any chair, they have to shuffle their feet around to find their balance point. In doing so, they generally place their hand on the arm of the chair for support. Getting out of a wheelchair is even more difficult because it is less stable than a stationary chair. If the joystick is inadvertently bumped during this process, the chair could push or pull the person, which might very likely cause an injury. Although some electric wheelchairs have been equipped with a disable switch located adjacent the joystick, wheelchair occupants often forget to use this.
It would therefore be desirable to achieve automatic immobilization of the wheelchair when the occupant arises from a seated position in the chair. “Dead man's” switches earlier proposed to achieve this goal have employed weight sensors within the seat of the chair. However, when the wheelchair travels rapidly over a bump, the transient release of downward force upon the seat may trigger a dangerously abrupt braking action.
It is accordingly a primary object of the present invention to provide apparatus for automatically disabling and immobilizing an electric transporter when the occupant rises from a seated position in the transporter.
It is another object of this invention to provide apparatus as in the foregoing object which enable the transporter occupant to easily restore normal operation of the transporter when re-seated therein.
It is a further object of the present invention to provide apparatus of the aforesaid nature which can be inexpensively installed onto existing electric transporters.
These objects and other objects and advantages of the invention will be apparent from the following description.